Construction Hard hat safety air conditioned insert by NBD (COLDIE) CAI. 

RICHARD COURTEMANCHE  professor of Concordia university for neuroscience research said the cooling system is  "EXCELLENT".

2 hours cooling before changing cartridge.

Averages on testings done 2014-2015

Temperature ranges.                       Outside temp.                 Inside helmet temp.

   ¼hour                                                          34.1                                 22.5

1/2 hour                                                           34.2                                24.3

1 hour                                                               34.3                                 27.2

1.1/4 hour                                                        35.5                                 28

1.1/2 hours                                                      35.6                                 28.3

1.3/4 hours                                                      36.1                                 29.1

2 hours                                                             36.2                                 30.7


Cerebral Changes During Exercise in

the Heat

Bodil Nielsen and Lars Nybo

Institute of Exercise and Sport Sciences, University of Copenhagen, Copenhagen, Denmark

Abstract This review focuses on cerebral changes during combined exercise and heat

stress, and their relation to fatigue. Dynamic exercise can elevate the core temperature

rapidly and high internal body temperatures seem to be an independent

cause of fatigue during exercise in hot environments. Thus, in laboratory settings,

trained participants become exhausted when they reach a core temperature of

~40°C. The observation that exercise-induced hyperthermia reduces the central

activation percentage during maximal isometric muscle contractions supports the

idea that central fatigue is involved in the aetiology of hyperthermia-induced

fatigue. Thus, hyperthermia does not impair the ability of the muscles to generate

force, but sustained force production is lowered as a consequence of a reduced

neural drive from the CNS. During ongoing dynamic exercise in hot environments,

there is a gradual slowing of the electroencephalogram (EEG) whereas

hyperthermia does not affect the electromyogram. The frequency shift of the EEG

is highly correlated with the participants’ perception of exertion, which furthermore

may indicate that alterations in cerebral activity, rather than peripheral

fatigue, are associated with the hyperthermia-induced development of fatigue.

Cerebral blood flow is reduced by approximately 20% during exercise with

hyperthermia due to hyperventilation,which causes a lowering of the arterialCO2

pressure. However, in spite of the reduced blood flow, cerebral glucose and oxygen

uptake does not seem to be impaired. Removal of heat from the brain is also

an important function of the cerebral blood flow and the lowered perfusion of the

brain during exercise and heat stress appears to reduce heat removal by the venous

blood. Heat is consequently stored in the brain. The causal relationship between

the circulatory changes, the EEG changes and the hyperthermia-induced central

fatigue is at the present not well understood and future studies should focus on

this aspect.

LEADING ARTICLE Sports Med 2003; 33 (1): 1-11


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